• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2002.08a
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• pp.54-63
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• 2002

Post-harvest technology for rice was focused on in-bin drying system, which consists of about 100, 000 facilities in 1980s. The modernized Rice Processing Complex (RPC) and Drying Storage Center (DSC) became popular for rice dry, storage, process and distribution from 1990s. However, the percentage of artificial drying for rice is 48% (2001) and the ability of bulk storage is about 15%. Therefore it is necessary to build enough drying and bulk storage facilities. The definition of high quality rice is to satisfy both good appearance and good taste. The index for good taste in rice is a below 7% of protein, 17-20% of amylose, 15.5-16.5% of moisture contents and high concentration of Mg and K. To obtain a high quality rice, it is absolutely needed to integrate high technologies including breeding program, cropping methods, harvesting time, drying, storing and processing methodologies. Generally, consumers prefer to rice retaining below b value of 5 in colorimetry, and the whiteness, the hardness and the moisture contents of rice are in order of consumer preference in rice quality. By selection of rice cultivars according to acceptable quality, the periods between harvesting time and drying reduced up to about 20 days. Therefore it is necessary to develop a low temperature grain drying system in order to (1) increase the rate of artificial rice drying up to 85%, (2) keep the drying temperature of below 45C, (3) maintain high quality in rice and (4) save energy consumption. Bulk storage facilities with low temperature storage system (7-15C) for rice using grain cooler should be built to reduce labor for handling and transportation and to keep a quality of rice. In the cooled rice, there is no loss of grain quality due to respiration, insect and microorganism, which results in high quality rice containing 16% of moisture contents all year round. In addition, introducing a low temperature milling system reduced the percentage of broken rice to 2% and increased the percentage of head rice to 3% because of proper hardness of grain. It has been noted that the broken rice and cracking reduced significantly by using low pressure milling and wet milling. Our mission for improving rice market competitiveness goes to (1) produce environment friendly, functional rice cultivars, (2) establish a grade standard of rice quality, (3) breed a new cultivar for consumer oriented and (4) extend the period of storage and shelf life of rice during postharvest.

• Polymer(Korea)
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• v.24 no.1
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• pp.72-81
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• 2000

Benzoic acid polyester/lactone polyol were synthesized by polycaprolactone 0201 as diol, trimethylolpropane as triol, adipic acid as dibasic acid, and benzoic acid as monobasic acid. Polyisocyanate prepolymer Desmodur N-100 of HDI-biuret type was used in this study. Two-component polyurethane coatings were prepared by blending benzoic acid polyester/polycaprolactone, polyisocyanate, wetting/dispersing agent, white pigment, and flowing agent. Various properties were examined on the film coated with the prepared polyurethane. They showed excellent physical properties such as abrasion resistance, accelerated weathering resistance, and yellowness index. They also showed good physical properties such as flexibility, impact resistance, 60$^{\circ}$ specular gloss, cross hatch adhesion, hydrocarbon resistance, and lightness index difference. Hardness of coating showed a little poor character. The introduction of polycaprolactone 0201 as diol in the polyurethane coatings improved the hydrocarbon resistance, impact resistance, and flexibility of coatings. According to the drying and curing behavior with the contents of benzoic acid, they seem to have reasonable coating properties such as drying time of 2 to 4 hours and pot-life time of 20 to 37 hours.

• Clinical and Experimental Reproductive Medicine
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• v.51 no.1
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• pp.42-47
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• 2024

Objective: This study evaluated the effects of temperature and storage time on the quality and DNA integrity of freeze-dried sperm from individuals with normozoospermia. Methods: Normal sperm samples from 15 men aged 24 to 40 years were studied. Each sample was divided into six groups: fresh, freezing (frozen in liquid nitrogen), freeze-dried then preserved at room temperature for 1 month (FD-1m-RT), freeze-dried then preserved at room temperature for 2 months (FD-2m-RT), freeze-dried then preserved at 4 ℃ for 1 month (FD-1m-4 ℃), and freeze-dried then preserved at 4 ℃ for 2 months (FD-2m-4 ℃). The morphology, progressive motility, vitality, and DNA integrity of the sperm were evaluated in all groups. Results: In all freeze-dried groups, sperm cells were immotile after rehydration. The freeze-dried groups also showed significantly less sperm vitality than the fresh and frozen groups. Significantly more morphological sperm abnormalities were found in the freeze-dried groups, but freeze-drying did not lead to a significantly higher DNA fragmentation index (DFI). The DFI was significantly higher in the FD-2m-RT group than in the other freeze-dried groups. Conclusion: The freeze-drying method preserved the integrity of sperm DNA. The temperature and duration of storage were also identified as factors that influenced the DFI. Accordingly, more research is needed on ways to improve sperm quality in the freeze-drying process.

• Journal of Pharmaceutical Investigation
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• v.37 no.2
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• pp.113-117
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• 2007

The aim of this study was to investigate the effect of different wall material on the microencapsulation efficiency of microcapsules containing fish oil. The present work reports on the microencapsulation of fish oil by spray drying using hydroxypropyl methylcellulose (HPMC) 2910, maltodextrin, gelatin, sodium caseinate as wall materials. The emulsion stability was assessed by emulsion stability index value (ESI). The microstructural properties of microcapsules was evaluated by scanning electron microscopy (SEM) and microencapsulation efficiency (ME) was assessed by soxhlet method. The highest ESI and ME were observed in the case of a 1:1 gelatin/sodium caseinate ratio and 1:1 glycerin fatty acid ester/lecithin ratio, and ME of microcapsules was increased with increasing the ESI of emulsion. Thus, the stability of emulsion was a critical factor for the encapsulation of fish oil.

• Journal of the Korean Chemical Society
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• v.64 no.5
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• pp.259-266
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• 2020

The main purpose of this study is to examine the different physicochemical properties of spray-dried products. The carrier agents and powders after the spray-drying process were analyzed for encapsulation yield, moisture content, color parameters, total polyphenol content (TPC), antioxidant capacity (AC), bulk density, flowability, wettability, hygroscopicity, water solubility index (WSI), particle size and microstructure. The spray-drying process was carried out with different carrier agents including maltodextrin (MD) and the combination of maltodextrin and gum arabic (MD-GA) with MA/GA ratio of 70/30, dried at the inlet/outlet air temperature of 160 ℃/70 ℃, 4 bar, airflow rate of 70 ㎥·h^-1 and feed flow rate of 750 mL·h^-1. The results showed that the different carrier agents have significant influences on the physicochemical properties of the powder produced by the spray-drying method. In there, while the values of recovery efficiency and flowability of spray-dried products from MD are higher than those of spray-dried products from MD-GA combination, the opposite is true for the values of TPC, AC, bulk density and wettability, whereas hygroscopicity and WSI values are equally represented in both products.

• Journal of Biosystems Engineering
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• v.39 no.2
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• pp.96-100
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• 2014

Purpose: The objective of this study was to develop a classification index and the grade levels for a five-grade energy efficiency classification of agricultural dryers in Korea. Methods: The classification index and the grade levels were determined by using the performance test data published by the FACT over the last eight years to reflect a state of the art technology for agricultural dryers in Korea. The five grades were designed to have the classified dryers distributed normally over the grades with 15% for the $1^{st}$ grade, 20% for the $2^{nd}$ grade, 30% for the $3^{rd}$ grade, 20% for the $4^{th}$ grade and 15% for the $5^{th}$ grade. Results: The classification index was defined as the total amount of fuel and electrical energy consumed per 1% of the wet basis moisture content evaporated from a unit mass of grain or agricultural crops during the drying process: 1 MT of paddy rice for grain dryers and 1 kg of red pepper for agricultural crop dryers as the standard mass. Conclusions: The grade levels for the five-grade energy efficiency classification of grain dryers, kerosene dryers, and electric dryers were proposed in terms of the classification index value.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.63-65
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• 2010

The purpose of the study was to analyze dry shrinkage of HVFAC (high volume fly ash concrete) with admixture to improve early strength. The results were as follows. In dry shrinkage of HVFAC with admixture to improve early strength, F3 had the lowest amount of dry shrinkage. The next is in order of Plain, F3-f15 and F3-f15r5. The study used index function modelfor analysis on dry shrinkage. Coefficient of determination was more than 0.97 in all mix, which made it possible to have a good estimation.

• Journal of the Korean Ceramic Society
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• v.30 no.9
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• pp.775-783
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• 1993

TiO2-SiO2 system anti-reflective(AR) film was prepared to decrease reflectance on the glass surface. The experiments were carried out as fellow, 1) preparation & hydrolysis of TiO2-SiO2 system sols. 2) glass dipping, and 3) drying & heat treatment. We investigated the refractive index and thickness of film with viscosity, zeta-potential of sol, sol concentration, withdrawal speed, drying and heat treatment condition. As a result, we prepared good qualitative Quarter-Half-Quarter type anti-reflective film that had minimum, 0.02% and average reflectance, 0.087% in the visible region.

• Journal of Biosystems Engineering
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• v.21 no.2
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• pp.182-190
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• 1996

A macerating technique which can apply to the mechanical production system of the agricultural by-product was developed to increase the utilization of agricultural waste and solve the shortage problem in the forage supply for the livestock production. The macerating method is to shred the agricultural by-product by the two rolls which rotate at different speeds each other. The testing macerator was built and the optimum operating conditions are suggested. Results of this research are as follows: 1. The increase of the base roll speed and speed ratio between two rolls shows the better shredding index but decrease the drying rate. The optimum conditions of the base roll speed and the speed ratio between two rolls for the rice straw are 1200 rpm and 1.7-2.0 respectively. 2. The macerated alfalfa was dried to the 15%(w.b.) within 3 hrs in a field at speed ratio of rolls, 2:1 and base roll speed, 1800rpm. 3. The milled surface and straight knurled surface for the macerating roll have same effect on the drying rate of material. Both rolls have self-cleaning functions during operation.

• Journal of the Korean Applied Science and Technology
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• v.12 no.1
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• pp.19-27
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• 1995

The 2-packaged polyurethane coatings were synthesized, blending pheylmodified polyesters(of which synthetic methods were reported in the previous paper), Desmodur L-75(polyisocyanate wide1y used for coatings), wetting-dispersing agent, white pigment. etc. A variety of coating properties were tested for the coating treatment polyurethane coationgs. Compared with conventional 2-packaged polyure-thane coating, abrasion resistance and lightness index difference of the ones synthesized in the present work were somewhat decreased, but the coating properties such as hardness, gloss specular, cross hatch adhesion. etc. were improved. Especially, resistance against chemical reagents and salt were strikingly improved. In addition. the coationgs had short drying time and long pot-life. This shows that the coationgs are appropriate for rapid drying coatings.